Biomedical subjects

Y Kitazawa

Publications and source records attributed to Y Kitazawa.

At least 127 records · Page 7Linked to original sources

PubMed1994

Reproducibility of measurements by laser scanning tomography in eyes before and after pilocarpine treatment.

We measured the optic disc topography of ten eyes from ten normal, healthy volunteers before and 1 h after pilocarpine treatment, using the Heidelberg Retina Tomograph. The mean age of the volunteers was 26.4 years, and the mean pupil diameter before and after pilocarpine treatment was 5.5 mm and 3.2 mm, respectively. We collected a series of five to ten consecutive topographic images of the optic disc for each eye, before and after treatment. The mean coefficients of variation of the measurements for the three randomly selected topographic images before pilocarpine treatment were 7.28% (1.25-15.15%) for cup volume and 7.33% (1.44-15.24%) for mean depth inside the cup margin. After treatment, the means were 12.25% (3.24-21.80%) and 12.88% (0.66-21.71%), respectively. Statistically significant differences were observed (P < 0.05) between the pre- and post-treatment coefficients of variation. These results suggest that care should be taken to evaluate the disc changes in eyes treated with pilocarpine.

Adult↗

PubMed1994

A risk-benefit assessment of drugs used in the management of glaucoma.

All antiglaucoma drugs are able to lower intraocular pressure (IOP) to variable degrees. However, all of them can possibly produce ocular and/or systemic adverse effects, some of which are not acceptable. Therefore, the drug or the combination of drugs which is efficacious enough to achieve the target IOP and have no or negligible adverse effects should be identified for each glaucoma patient, considering their ocular (e.g. the stage of glaucomatous damage, refraction) and systemic (e.g. age, cardiovascular disease) conditions.

Adrenergic Agonists↗

PubMed1994

Effects of endothelin-1 on intraocular pressure and aqueous humor dynamics in the rabbit eye.

The effects of endothelin-1 (ET-1) on intraocular pressure (IOP) and aqueous humor dynamics were studied in the rabbit eye. The intravitreal injection of 10(-5) M ET-1 (20 microliters) produced a biphasic IOP response consisting of an initial rise of 1 to 2 hours in duration, and a subsequent prolonged reduction lasting for more than 96 hours. Aqueous humor dynamics were determined 24 hours after the 10(-5) M ET-1 injection. Aqueous humor formation, measured fluorophotometrically, was decreased by 58%. Total outflow facility increased by 94%, according to measurement by two-level constant pressure perfusion. The change of uveoscleral outflow determined by fluorescein-dextran perfusion was not significant. The decrease in aqueous flow and the increase in total facility accounted for most of the IOP reduction after the ET-1 injection. Endothelin, which is endogenously present in the eye, may play a role in the regulation of intraocular pressure.

Animals↗

PubMed1994

Sectorial blood supply to the monkey optic disc surface from the cilioretinal artery.

The cilioretinal artery in one monkey eye (left) was observed using fluorescein videoangiography and a scanning laser ophthalmoscope, and was further evaluated by scanning electron microscopy after microvascular corrosion casting. Following intravenous injection of fluorescent dye, a choroidal flush was observed at 5.7 seconds. Appearance of the dye in two cilioretinal arteries at the edge of the temporal optic disc was at 5.9 seconds, and the capillary phase of these arteries, at 6.4 seconds. The dye was first observed in the central retinal artery at 6.9 seconds. The cilioretinal arteries directly supplied the microcirculation of the temporal quadrant of the optic disc and the retinal vasculature in the disc-macular area. The vascular casting showed the entire course of the cilioretinal arteries in the retina. The cilioretinal arteries entered the temporal edge of the retrobulbar optic nerve head and branched to the prelaminar and the temporal edge of the optic disc.

Animals↗

PubMed1994

[Safety and ocular hypotensive effect of a new prostaglandin analogue, S-1033, in normal volunteers].

We conducted a prospective, placebo-controlled, double-masked study to investigate the ocular hypotensive effect and safety of a new prostaglandin analogue, S-1033, in healthy human volunteers. In a single-dose, dose-finding study, where 0.1%, 0.2%, 0.3%, or 0.4% of S-1033 and the vehicle ophthalmic solution was instilled in each one eye of six adult male volunteers and vehicle solution alone in the fellow eye, 0.3% solution showed a significant ocular hypotensive effect at 1, 2, and 8 hours following the instillation and 0.4% solution showed a similar effect at 4 hours after the instillation. The following multiple-dose study, where 0.3% S-1033 solution was instilled twice daily for 8 days in one eye of six volunteers and the vehicle in the follow eye, revealed a significant, continuous intraocular pressure (IOP) reduction. Mild, transient conjunctival hyperemia and slight ocular discomfort developed in some cases, but they were minor. These results indicate that S-1033 has a significant ocular hypotensive effect without substantial adverse effects and the new compound seems to deserve further investigation as a possible anti-glaucoma medication.

Depression, Chemical↗

PubMed1994

Stages in the development of the rat lung: morphometric, light and electron microscopic studies.

Ontogenic changes of the pulmonary epithelium of the rat, ranging from fetal day 15 to 1 hour after birth (21st day), were observed using light and electron microscopy as well as morphometric analysis on the area occupied by terminal segments of epithelial tubes or by alveolar sacs (ATETAS) in the terminal region of the lung. The development of the lung was classified into four stages. In the pseudoglandular period (fetal days 15 and 16), epithelial tubes lined by columnar epithelium were not yet associated with blood capillaries. The percentages occupied by ATETASs in the terminal region of the lung were 15.3% and 15.7%, respectively, on fetal days 15 and 16. In the precanalicular period (fetal days 17 and 18), blood capillaries began to appose to epithelial tubes lined by cuboidal epithelium. Small osmiophilic lamellar bodies (OLBs) emerged in cuboidal epithelial cells (type II cells) on day 18. The percentages occupied by ATETAS were 24.9% and 25.5%, respectively, on days 17 and 18. In canalicular period (fetal days 19 and 20), sac-like end segments showed progressive thinning of the epithelial linings, and the amount of interstital tissues markedly decreased. The epithelial cells differentiated into squamous, or type I cells, and type II cells containing OLBs. Extrusion of OLBs was recognized on day 20. Most of the capillaries were located close to the epithelial linings. The thickness of the blood-air barrier on day 20 was 10 times that of the adult. The percentages occupied by ATETAS were 35.8% and 38.5%, respectively, on days 19 and 20. In the terminal sac period (in neonate), the wall of terminal sacs showed a thin epithelial lining. Blood capillaries protruded close to the air-way surfaces. The thickness of the blood-air barrier was 3.5 times as thick as that of adult. The percentage occupied by ATETAS was 53.1% of the total terminal region of the lung. When the area occupied by ATETAS at a given day was compared to the area of the adult, the percentage on day 20 was approximately 60% of the adult value, whereas the percentage in neonates was 85%. This suggested that a remarkable transformation took place in ATETAS between day 20 and neonate. In addition to the four periods mentioned above, we also discussed the embryonic and alveolar periods in the development of the rat lung.

Animals↗

PubMed1994

[Biphasic intraocular pressure response to intravitreal injection of endothelin-1].

Endothelin-1 (ET-1) reduces intraocular pressure (IOP) in animals when administered topically. The time course of IOP induced by ET-1, however, has not been fully elucidated. We studied the IOP response to different doses of ET-1 ranging from 10(-7) to 10(-4)M (5 micrograms to 5 ng) intravitreally injected in rabbits. In each animal one eyes received 20 microliters of ET-1 solution and the contralateral eye received same amount of vehicle in a randomized, masked fashion. IOP was measured by a pneumotonometer prior to and periodically for at least 72 hours after the intravitreal injection. ET-1 in 10(-4) and 10(-5) molar concentration elicited a biphasic IOP response consisting of an initial rise of 1 to 2 hours duration, and a subsequent prolonged reduction lasting for more than 72 hours. 3 x 10(-6) and 10(-6) M solution resulted in a prolonged IOP reduction without an early IOP rise. No significant IOP change was induced by 10(-7) M solution or vehicle. Both IOP rise and reduction were significantly related to the dose of ET-1.

Animals↗

PubMed1994

[Trabeculectomy for normal-tension glaucoma].

We prospectively investigated the postoperative intraocular pressure (IOP) level, visual prognosis, and complications of trabeculectomy with adjunctive mitomycin C in normal-tension glaucoma. The subjects were 42 eyes of 29 patients who underwent surgery with 0.2 mg mitomycin C as an adjunct and were followed for 12-30 months (mean: 20.6 months). The preoperative IOP was 11-18 mmHg with a mean (+/- standard deviation) of 13.9 +/- 1.5 mmHg. The IOP decreased to 4-16 mmHg with a mean (+/- standard deviation) of 7.9 +/- 2.6 mmHg. The magnitude of the IOP reduction ranged from -1 to 10 mmHg with a mean of 6.0 mmHg. The number of eyes receiving ocular hypotensive medication decreased remarkably from 32 eyes preoperatively to 2 eyes postoperatively. The visual field deteriorated postoperatively in 2 eyes (4.8%) whose IOP was around 8 and 9 mmHg, respectively. Cataract progressed in 8 eyes (19.0%) and hypotonous maculopathy developed in 5 eyes (11.9%). Because the postoperative IOP level is close to the IOP value that is allegedly beneficial in preserving visual function in normal-tension glaucoma, the surgery is worth further consideration as a potent treatment for the disease.

Adult↗

PubMed1994

[Interaction between a prostaglandin F2 alpha derivative, UF-021, and pilocarpine in ocular hypotensive therapy].

We investigated the ocular hypotensive effect of concomitant use of pilocarpine and UF-021, a prostaglandin-related compound, in 10 cases (20 eyes) of primary open-angle glaucoma or ocular hypertension. Following a 2- to 4-week-washout of all anti-glaucoma medication, 0.12% UF-021 was instilled twice daily into both eyes of 5 patients and 1% pilocarpine four times daily in 10 eyes of the remaining 5 patients for 2 weeks. Then both eye-drops were used concomitantly for the subsequent 2 weeks. Intraocular pressure (IOP) measurement and slit-lamp examination were carried out from one hour prior to the instillation to 4 hours after the instillation at the end of the washout period, the single-use period, and the concomitant-use period. Although no significant difference was found between IOPs of the single-use and concomitant use periods at each measurement time point, a significant difference was found between them when all the measured IOP values were pooled. No changes in episcleral venous pressure nor adverse effects were noted. We concluded that the concomitant use of pilocarpine and UF-021 causes an additive ocular hypotensive effect in clinical settings.

Adult↗

PubMed1994

[Sectorial blood supply of the monkey optic disc surface from the cilioretinal artery].

The cilioretinal artery in a monkey eye was observed by scanning laser ophthalmoscope video-angiography and evaluated by microvascular corrosion casting. After an intravenous injection of fluorescent dye, we observed a choroidal flush at 5.7 seconds, appearance of the dye in two cilioretinal arteries from the edge of the temporal optic disc at 5.9 seconds, and the capillary phase of cilioretinal arteries at 6.4 seconds. The dye was first observed in the central retinal artery at 6.9 seconds. The cilioretinal arteries directly supplied the microcirculation of the temporal disc in a sector-shaped pattern and the retinal vasculature in the disc-macular area. The vascular casting showed the total course of the cilioretinal arteries from the posterior ciliary arteries to the retina. The cilioretinal arteries entered the temporal edge of the retrobulbar optic nerve head, gave off some branches at the prelaminar portion, and appeared at the temporal edge of the optic disc.

Animals↗

PubMed1994

[Analysis of therapeutic prognosis of primary open-angle glaucoma by the proportional hazards model and the life-table method].

We retrospectively analyzed the therapeutic prognosis of primary open-angle glaucoma by the life-table method and the proportional hazards model. One hundred and eight patients (202 eyes) were studied. The follow-up period ranged from 6 to 125 months (40 +/- 25 months: mean +/- SD). The Kaplan-Meier life-table method indicated that therapeutic prognosis was significantly related to pretreatment intraocular pressure (IOP) and visual field defect, and that more intensive treatment was needed for higher IOP and more deteriorated visual field defect. Analysis by the proportional hazards model showed that pretreatment IOP and mean deviation (MD) measured by static perimetry were significant prognostic factors for non-surgical treatment and that the hazard ratios were 1.29-1.31 for a 5 mmHg rise in IOP and 1.44-1.83 for a 10 dB fall in MD. We concluded that the therapeutic prognosis of primary open-angle glaucoma is highly related to the level of IOP and the severity of visual field defect at the time of diagnosis.

Adult↗

PubMed1993

Low-dose and high-dose mitomycin trabeculectomy as an initial surgery in primary open-angle glaucoma.

PURPOSE: The purpose of the study is to determine the optimum regimen of intraoperative administration of mitomycin as an adjunct to trabeculectomy. METHODS: Of 11 patients with primary open-angle glaucoma, 22 eyes that had not undergone any surgical intervention were included. In each patient, one eye was randomly allocated to a mitomycin 0.2-mg group and the fellow eye to a mitomycin 0.02-mg group. Mitomycin was applied for 5 minutes only once during trabeculectomy. The follow-up period was 6 to 17 months. RESULTS: Eleven (100%) eyes in the 0.2-mg group and 7 (63.6%) in the 0.02-mg group achieved successful control of intraocular pressure with or without topical antiglaucoma medication. Transient hypotony maculopathy (18%) and cataract progression (18%) were noted in the 0.2-mg group exclusively. The incidence of other complications was similar between the two groups. CONCLUSION: These data suggest that the most appropriate dose of mitomycin for primary surgery seems to be in between the two doses tested in the current study.

Administration, Topical↗

PubMed1993

Changes in retinal nerve fiber layer thickness after reduction of intraocular pressure in chronic open-angle glaucoma.

PURPOSE: The authors evaluated the relative nerve fiber layer height changes in glaucomatous eyes after reduction of intraocular pressure (IOP) after trabeculectomy using image analysis techniques. METHODS: Optic disc topography and relative nerve fiber layer height of 12 eyes of 12 patients with chronic open-angle glaucoma were measured using a Rodenstock optic nerve head analyzer and Caprioli's program for nerve fiber layer height determination before trabeculectomy and at 2 or more months after surgery. RESULTS: Changes in relative nerve fiber layer height after surgery, as well as those in cup volume and rim area, showed statistically significant correlation with the degree of reduction of IOP (Spearman's correlation coefficient = 0.66; P < 0.05). Changes in the mean deviation of Humphrey visual field showed a slight correlation with IOP reduction (Spearman's correlation coefficient = 0.55; P < 0.1). CONCLUSION: Nerve fiber layer height changes that may occur after trabeculectomy are pressure-dependent.

Adult↗

PubMed1993

An analysis of the relationship between high-pass resolution perimetry and neuroretinal rim area in normal-tension glaucoma.

We evaluated the reproducibility of measurements of the visual function index, 'functional channels', of high-pass resolution perimetry and the correlation between functional channels and topographic changes of the optic nerve head, particularly on the neuroretinal rim area. The median coefficient of variation for the six intra-individual measurements of functional channels with high-pass resolution perimetry was 9.5%. In 26 eyes of 18 normal-tension glaucoma patients, functional channels showed statistically significant correlation with the neuroretinal rim area (rim area) of the optic disc measured by a Rodenstock Optic Nerve Head Analyzer. These results suggested that functional channels of high-pass resolution perimetry may be a useful new parameter for evaluating visual function of glaucoma patients.

Adult↗

PubMed1993

Double-masked comparative study of UF-021 and timolol ophthalmic solutions in patients with primary open-angle glaucoma or ocular hypertension.

A double-masked comparative clinical study of UF-021 (Rescula), a unique prostaglandin-related compound, was carried out at 18 centers with timolol maleate 0.5% ophthalmic solution as an active reference drug. After a wash-out period, UF-021 (0.12%) or timolol (0.5%) was given topically twice a day for 12 weeks to 158 patients with primary open-angle glaucoma or ocular hypertension, in a randomized double-masked manner. Both groups showed a significant reduction in intraocular pressure from the second week to the end of the study. In overall improvement rating, 91.4% of the cases (64/70) in the UF-021 group and 88.3% (68/77) in the timolol group were judged to be "Extremely improved" or "Improved". Five and 4 cases reported having side effects in the UF-021 and timolol groups, respectively, but none of the cases required any change or discontinuation of treatment. While UF-021 did not affect blood pressure, both systolic and diastolic blood pressures in the timolol group were significantly decreased. These results suggest that UF-021 (0.12%) has the potential to lower intraocular pressure equivalent to timolol (0.5%), while having no effect on cardiovascular functions.

Administration, Topical↗

PubMed1993

Ocular hypotensive effect of PhXA41 in patients with ocular hypertension or primary open-angle glaucoma.

A study was carried out to assess the clinical efficacy of PhXA41, a new phenyl-substituted prostaglandin F2 alpha-isopropyl ester analogue, using a single administration in 35 subjects with ocular hypertension or primary open-angle glaucoma. PhXA41 caused a dose-dependent intraocular pressure (IOP) reduction which continued 24 hours or more after administration. The mean IOP reduction 8 hours after treatment compared with the baseline IOP was 3.4, 4.9 and 5.9 mmHg for the doses of 25, 50 and 100 micrograms/ml, respectively. Although slight conjunctival hyperemia occurred in some patients, it disappeared by the next day with no treatment. No aqueous flare or cells were detected, no significant change in pupillary diameter was found, and no systemic symptom was reported. Thus, PhXA41 was well tolerated in subjects with ocular hypertension or primary open-angle glaucoma. Furthermore, its IOP-reducing effect was so long-lasting that a once daily application may suffice for clinical use.

Adult↗

PubMed1993

[Comparison of high-pass resolution perimetry and differential light sensitivity perimetry in glaucoma patients].

High-pass resolution perimetry (HRP) enables one to estimate the number of functioning retinal ganglion-cells. We investigated the correlation between HRP and Humphrey Field Analyzer 630 in 35 eyes of 23 primary open-angle glaucoma and 75 eyes of 46 normal-tension glaucoma patients. In a total of 110 eyes, both functional channels and global deviation of HRP were significantly correlated with MD (r = 0.74, p < 0.01: r = -0.71, p < 0.01, respectively). Local deviation of HRP was also significantly correlated with corrected pattern standard deviation (r = 0.77, p < 0.01). These correlations tended to be higher in eyes with more advanced field changes than in those with fewer changes. These results indicate that HRP may be useful for evaluation of glaucomatous visual field abnormalities. The observed discrepancies between the two different methods in early stage glaucoma may be attributable to differences in physiological factors tested in these methods.

Adult↗

PubMed1993

Clinical evaluation of the effects of direct hemoperfusion on amino acid profiles.

We observed significant changes in serial aminograms during direct hemoperfusion (DHP) in clinical cases and decided to evaluate the effects of the procedure on amino acid profiles. DHP at 100 ml/min was carried out for 6 h in patients with drug intoxications. Pre- and post-column aminograms were obtained 0.5, 1, 2, 3, 4, 5 and 6 h from the beginning of DHP. Nonmolecular-weight-dependent adsorption of some amino acids to the column was observed. Methionine (MET), isoleucine (ILE), leucine (LEU), tyrosine (TYR), phenylalanine (PHE) and arginine (ARG) had high adsorption rates. Blood concentrations of TRY, PHE, TRY and histidine (HIS) were significantly reduced. Although both branched-chain amino acids (BCAA) and aromatic amino acids (AAA) were initially adsorbed by the column, AAA recovery was slow.

Adsorption↗